Spend Less Time Building and More Time Shooting.

The Stern Defense SD Mod 4 9mm Upper Receiver is a complete, ready to go, upper receiver solution for those looking to spend less time building and more time shooting.

The 4 inch, 1-10 twist, Melonited barrel, is free float in a 4in M-LOK handguard attached to a 7075-T6 forged aluminum receiver. On the end of the barrel mounted on the ½-36 threads is a 1.75” long, 1.2” diameter blast can designed to direct the short barreled blast away from the shooter.

4in barrel

4in M-LOK Free Float handguard

Complete assembly with 9mm bolt and charging handle

½-36 muzzle thread pitch

1.75” long by 1.2” diameter blast can muzzle device

SD BU9 9mm Bolt

Cartridge: 9mm Nato

Included in the upper receiver is charging handle and the Stern Defense 9mm Bolt which is compatible with both Glock and Colt SMG magazines, has a Melonite finish, and is works in conjunction with the Law Tactical Folding Adapter. The Stern Defense SD Mod 4 9mm Upper Receiver is made in the U.S.A.